The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
A transmission-mounted electric device (TMED) type hybrid vehicle having a DCT is configured such that, in a state in which an engine, a motor, and a DCT are arranged in sequence, an engine clutch is provided between the engine and the motor, and the motor is mounted to the transmission with respect to the engine clutch. When the TMED-type hybrid DCT vehicle is downshifted to a lower shift stage as it slows down on the uphill road, the vehicle in a forward running state in which the vehicle's speed is above zero “0” becomes to slide backward (namely, a negative speed). We have discovered that, when the DCT is downshifted while the vehicle slows down on the uphill road, gear-shifting may be delayed due to an excessive increase in motor speed, thereby causing the vehicle to increasingly slide backward (i.e., increase in the negative speed).
This is because, if the vehicle already begins to slide backward when a controller for controlling the DCT determines that the vehicle still travels forward and thus performs control for increasing a motor torque to rapidly synchronize the motor speed with a desired shift stage input shaft speed, the desired shift stage input shaft speed suddenly becomes a negative speed lower than a current shift stage input shaft speed as well as the motor speed, in which case the motor speed is unnecessarily increased since two clutches of the DCT are released, and gear shifting is delayed since it takes much time until the motor speed is synchronized with the desired shift stage input shaft speed, thereby causing the vehicle to continuously slide backward while the gear shifting is delayed.
The foregoing is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art.